The report by Benca and colleagues1 in this issue of the Archives is a comprehensive, meta-analytic review of sleep research on psychiatric disorders that uses visual scoring methods published during the past two decades. Based on an analysis of 177 studies describing 7151 patients and healthy control subjects, the authors conclude that although no single sleep parameter (such as rapid eye movement [REM] latency) appeared to have absolute specificity for any particular psychiatric disorder (such as depression), "patterns of sleep disturbances associated with categories of psychiatric illnesses were observed," and that sleep in patients with affective disorders differed most frequently and significantly from sleep in normal controls.

This report may be the first of its kind in biological psychiatry on such a large scale, addressing sleep not only in depressed patients (who constitute almost half of the research subjects), but also in patients with primary insomnia, anxiety disorders, schizophrenia,